Self-service terminal equipments have been widely applied in various fields, and self-service terminals are generally provided with printing devices, e.g. an Automated Teller Machine (ATM) is capable of printing a transaction voucher, and a self-service telephone bill enquiry machine is capable of printing a telephone bill etc.
Currently, such self-service terminal equipments with a printing function generally have the following problem: if a user interferes with paper output during a printing process, a printing device fault may be caused, e.g. when a user blocks a paper exit and stops paper output during a printing process, paper jam and stacking are easily caused in an automatic terminal exit and can be hardly observed outside a self-service terminal equipment, thus paper is blocked between the printer paper exit and the self-service terminal paper exit, and the next printing operation cannot be performed. In addition, if a user pulls out a piece of paper being printed during a printing process, paper deflection is easily caused to result in paper jam or unused paper will be pulled out continuously to cause paper waste.
To solve the problem, Chinese Patent Publication Number CN201841763U puts forward a paper discharge mechanism and a printing device and a terminal equipment having the paper discharge mechanism. As shown in FIG. 1, the paper discharge mechanism comprises a paper jam detection mechanism 31′ and a paper pullout detection mechanism 32′, and a paper discharging passage is formed therebetween, wherein the paper jam detection mechanism 31′ comprises a first passage plate 311′, a paper containing portion 311a′ containing a paper's bending portion on the first passage plate 311′ and a paper detector 312′ located on the paper containing portion 311a′; the paper pullout detection mechanism 32′ comprises a second passage plate 321′, a floating plate 322′ penetrating through the second passage plate 321′ and extending into the paper discharging passage, an elastic element 323′ that provides elasticity for the floating plate 322′ so that the floating plate 322′ has the trend of extending into the paper discharging passage, and a floating plate position detector 324′ located on the second passage plate 321′.
Paper used by a printing device is generally roll paper twisted on the periphery of a paper roll core, wherein paper with the inner surface as a printing side is called inside disposed paper and paper with the outer surface as a printing side is called outside disposed paper. FIG. 2a shows a curled state during an inside disposed paper printing process, wherein paper runs between a printing head 211 and a roller 212, and the printing head 211 is in contact with a paper printing surface P1. FIG. 2b shows a curled state during an outside disposed paper printing process, wherein paper runs between a printing head 211 and a roller 212 and the printing head 211 is in contact with a paper printing surface P2.
The inventors found that, when the paper as shown in FIG. 2a is used during a printing process, the leading end of the paper is curled toward the direction of the first passage plate 311′, thus the paper is easily blocked in the paper containing portion 311a′ of the paper jam detection mechanism to cause a printer fault of paper jam. Therefore, the paper jam mechanism is unreliable in conveyance.